Smash Mouth - All Star Lyrics Meaning

"Somebody once told me the world is gonna roll me.
I ain't the sharpest tool in the shed.
She was looking kind of dumb with her finger and her thumb
In the shape of an "L" on her forehead."

The fact that the person is referred to as 'Somebody' could imply that the narrator doesn't care who they were. Secondly, perhaps the world 'rolling' them means that the change of society might pin you under for a time. The narrator admits that they're not the smartest, yet believes that she's the dumb one for not seeing past his unintelligent appearance.

"Well the years start coming and they don't stop coming
Fed to the rules and I hit the ground running
Didn't make sense not to live for fun
Your brain gets smart but your head gets dumb
So much to do, so much to see
So what's wrong with taking the back streets?
You'll never know if you don't go
You'll never shine if you don't glow."

The narrator is now saying that the struggles in life won't stop coming. Even if they once thought that the rules of society could make things easier, they now think that they only live once and need to live life to the fullest.
There is so much more out there, so nothing is wrong with taking the backstreets, or the less traveled path. This may refer to breaking the rules of society, to stand out among the rest.

"Hey now, you're an all-star, get your game on, go play.
Hey now, you're a rock star, get the show on, get paid.
And all that glitters is gold.
Only shooting stars break the mold."

In accordance to the previous statement that you only live once, they felt the need to go out and make a name for yourself. And even the smallest idea could lead to a fortune, so they are saying to use opportunities when they appear, and that only someone who breaks the rules stands out.

"It's a cool place and they say it gets colder
You're bundled up now, wait till you get older
But the meteor men beg to differ
Judging by the hole in the satellite picture
The ice we skate is getting pretty thin
The water's getting warm so you might as well swim
My world's on fire, how about yours?
That's the way I like it and I never get bored."

Interpretation 1:
Life is harsh, and with age comes hardship. But today's society (Social media, etc.) seems to say that everyone's life is great and that only you face trials. But even from hardships come opportunities, and even if your world is filled with problems, you can learn from each one. With challenge comes pleasure and the harder things are, the more interesting things will be.

Interpretation 2:
This could also refer to global warming. "Meteor men" may refer to meteorologists. And even if the weather is getting colder, they swear that global warming is occurring, yet they have nothing to prove it with but "The hole in the satellite picture." Keeping information away from people keeps them from actually knowing the truth, but the narrator, by taking a different path, knows reality.

"Somebody once asked could I spare some change for gas?
I need to get myself away from this place.
I said yep. What a concept.
I could use a little fuel myself,
And we could all use a little change."

The person asking for the change is not just asking for physical change, but for a change in their life. (My theory is that this is the same 'somebody' from earlier who had called them a loser.) This person now understands the narrator, and wants to, like them, exit the normal flow of society. And the fuel represents the passion to go on, because even if the life of which the narrator is living requires much effort, it is worth it.

My interpretation of the whole song is this. At the beginning, "Somebody", perhaps a relative or friend, is telling them that they will never get far. But he indeed, does get far, and comes back later, saying that he likes the life that he is living. "Somebody" ponders this, realizes the truth, and joins them at the end of the song.